A tropical wave combined with an upper-level trough to result in enhanced thunderstorm activity across interior and western PR.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS SJU wrote it up.
A tropical wave combined with an upper-level trough to result in enhanced thunderstorm activity across interior and western PR.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS San Juan, PR wrote its last area forecast discussion before the first event at Sep 28, 4:00 PM AST, 0 minutes earlier.
Area Forecast Discussion National Weather Service San Juan PR 400 PM AST Mon Sep 28 2020 .SYNOPSIS... A tropical wave is currently moving across the region and causing showers and thunderstorms over the local and regional waters. An upper-level trough (TUTT) to the northwest of Puerto Rico is enhancing upper-level instability over Puerto Rico and the U.S. Virgin islands. The moisture associated with the tropical wave and the TUTT will induce showers and thunderstorms over the next several days. On Wednesday, another tropical wave will enter the area, thus an increase in showers and thunderstorms is expected. Then a slightly drier air mass by the end of the week, perhaps with some Saharan dust. && .SHORT TERM....Rest of Today through Wednesday... Moderate to heavy rainfall continues to move across the Caribbean waters this morning, with a few showers affecting land area. A tropical wave over the area is causing mid to upper-level clouds across eastern Puerto Rico and the eastern adjacent islands this morning. The cloud cover will delay the surface heating over the above areas, and therefore delay the development of showers and thunderstorms this afternoon. Breaks in clouds will enhance an already unstable environment as a result of the tropical wave and the mid to upper-level trough/TUTT to the northwest of Puerto Rico. Therefore, expect robust convection to develop across interior, western, and northwestern Puerto Rico. Also, scattered showers and thunderstorms are expected to develop over the metro areas of Puerto Rico and the U.S. Virgin Islands. Soils are saturated from previous days rainfall and any additionally rainfall today will likely cause urban and small stream flooding. Tuesday, the tropical wave and it's associated moisture is expected to be west of Puerto Rico; however, moisture trailing behind the wave will induce showers and thunderstorms tomorrow. Furthermore, the sea breeze convergence and diurnal effects will play a roll in the development of showers and thunderstorms. && PREV DISCUSSION... /issued 134 AM AST Mon Sep 28 2020/ .LONG TERM...Thursday through Tuesday... Somewhat drier air is expected to move in on Thursday into Friday, perhaps with some Saharan dust, which could limit the shower and thunderstorm activity across the area, especially when compared to what is forecast on Wednesday. That said, there is a tilted upper level trough that could help in the development of isolated thunderstorms. This upper trough is forecast by the global models to remain near the local islands through the long term period, though it could put PR and the USVI in the subsident side late in the weekend. There is also a strong SFC high pressure in the central Atlantic that will dominate the local wind flow, keeping us observing east to east southeast winds. The available moisture is expected to be near to slightly above normal for most of the long term period. So given the current setup, we can expect morning and overnight isolated to scattered showers with isolated thunderstorms over the waters, near the USVI and eastern PR, while each afternoon, showers and thunderstorms can be expected across portions of central and western PR and areas of sea breeze convergence. && .AVIATION... Prevailing VFR...SHRA/Isold TSRA en route over and btw the local islands and regional waters as a tropical wave moves across the region overnight through early Wednesday. SCT-BKN lyrs nr FL025..FL050...FL100...Max top btw FL250-FL350 with Isold TSRA. Mtn TOP obscr psbl interior sections of P with SHRA/Isold TSRA til 28/22Z. Wnds fm E-SE 10-15 kts with hir gust along coastal areas and also with passing SHRA/Isold TSRA...bcmg light/vrb aft 28/23Z. && .MARINE... Seas up to 5 feet for most of the local and regional waters. Winds up to 20 knots due to a tropical wave that is moving over the local waters. Winds will increase over the next several days as a result of the winds. The tropical wave is causing showers and thunderstorms across the local waters. Small craft operators are urged to exercise caution. There is a moderate risk of rip currents across the north beaches of PR and Culebra as well as eastern St Croix, low risk elsewhere. && .PRELIMINARY POINT TEMPS/POPS... SJU 79 91 79 88 / 50 50 40 40 STT 78 89 79 87 / 40 40 60 60 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. && SHORT TERM...TW LONG TERM....ERG PUBLIC DESK...CVB
Perspectivas sobre Condiciones Peligrosas del Tiempo Servicio Nacional de Meteorologia San Juan PR 139 AM AST lunes 28 de septiembre de 2020 AMZ710>745-PRZ001>013-291000- San Juan y Vecindad-Noreste-Sureste- Este Interior-Norte Central-Interior Central-Ponce y Vecindad- Noroeste-Oeste Interior-Mayaguez y Vecindad-Suroeste-Culebra-Vieques- Aguas cercanas y mar afuera del Atlantico y Caribe- 139 AM AST lunes 28 de septiembre de 2020 Esta perspectiva sobre las condiciones peligrosas del tiempo es para Puerto Rico y las aguas costeras del Atlantico. .Dia Uno...Hoy y esta noche .Tronadas...Existe la posibilidad de tronadas con lluvia fuerte y vientos en rafagas durate el dia a traves de la mayoria de las islas. .Inundaciones...Fuertes lluvias podrian resultar en inundaciones urbanas y riachuelos. .Viento...Vientos sostenidos de 20 mph (17 nudos) son anticipados a traves de las aguas del Atlantico y del Caribe. .Corrientes Marinas...Existe un riesgo moderado de corrientes marinas para las playas del norte de Puerto Rico y Culebra. .Calor...Se esperan indices de calor de hasta 106 grados sobre las areas urbanas y elevaciones bajas de Puerto Rico. .Dias dos hasta el siete...martes a domingo Una onda tropical y una vaguada en los niveles medios y altos traera aguaceros y tronadas adicionales desde tarde el martes hasta el miercolse, aumentando el potencial de inundaciones urbanas y de riachuelos. Se espera oleaje picado desde mitad hasta finales de la semana laboral. Riesgo moderado de corrientes marinas continuara por los proximos dias. .Comunicado sobre informacion reportada por observadores... No se anticipa activacion de observadores. Favor de reportar cualquier informacion sobre oleaje y corrientes marinas al Servicio Nacional de Meteorologia en San Juan mientras siguen las indicaciones de las autoridades locales y estatales. AMZ715-725-VIZ001-002-291000- San Tomas, San John e Islas Adyacentes- Santa Cruz- Aguas cercanas del Atlantico y aguas costeras adyacentes del Caribe- 139 AM AST lunes 28 de septiembre de 2020 Esta perspectiva sobre las condiciones peligrosas del tiempo es para Islas Virgenes Estadounidenses y las aguas costeras adyacentes. .Dia Uno...Hoy y esta noche .Tronadas...Existe el potencial de tronadas con lluvia fuerte y vientos en rafaga breves durante el dia a traves de las Islas Virgenes Americanas. .Inundaciones...Fuertes lluvias podrian resultar en inundaciones urbanas y riachuelos. .Viento...Vientos sostenidos de 20 mph (17 nudos) son anticipados a traves de las aguas del Atlantico y del Caribe. .Corrientes Marinas...Existe un riesgo moderado de corrientes marinas para las playas del este de Santa Cruz. .Calor...Se esperan indices de calor de hasta 102 grados en Santa Cruz. .Dias dos hasta el siete...martes a domingo Una onda tropical y una vaguada en los niveles medios y altos traera aguaceros y tronadas adicionales desde tarde el martes hasta el miercolse, aumentando el potencial de inundaciones urbanas y de cunetas. Se espera oleaje picado desde mitad hasta finales de la semana laboral. Riesgo moderado de corrientes marinas continuara por los proximos dias. .Comunicado sobre informacion reportada por observadores... No se anticipa activacion de observadores. Favor de reportar cualquier informacion sobre oleaje y corrientes marinas al Servicio Nacional de Meteorologia en San Juan mientras siguen las indicaciones de las autoridades locales y estatales.
Special Weather Statement
National Weather Service San Juan PR
343 PM AST Mon Sep 28 2020
PRZ007-009>011-282045-
Mayaguez and Vicinity-Western Interior-Southwest-Ponce and Vicinity-
343 PM AST Mon Sep 28 2020
...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT MUNICIPALITIES ALONG
THE WESTERN INTERIOR AND SOUTHWESTERN PUERTO RICO...
At 342 PM AST, strong thunderstorms were clustered 7 miles northeast
of Hormigueros. These storms were nearly stationary.
Winds in excess of 30 mph and pea size hail are possible with this
storm.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
LAT...LON 1829 6666 1802 6665 1802 6717 1803 6718
1803 6721 1806 6720 1807 6718 1807 6720
1809 6720 1811 6718 1813 6719 1815 6718
1817 6718 1820 6715 1829 6720
TIME...MOT...LOC 1942Z 119DEG 2KT 1820 6701
ICPComunicado Especial de las Condiciones del Tiempo Servicio Nacional de Meteorologia San Juan PR 343 PM AST lunes 28 de septiembre de 2020 PRZ007-009>011-282045- Mayaguez y Vecindad-Oeste Interior-Suroeste-Ponce y Vecindad- 343 PM AST lunes 28 de septiembre de 2020 ...UN AREA DE TRONADAS FUERTES AFECTARA LOS MUNICIPIOS DEL OESTE INTERIOR Y SUROESTE DE PUERTO RICO... A las 3:42 PM AST, tronadas fuertes estaban agrupadas a 7 millas al noreste de Hormigueros. Estas tronadas estaban casi estacionarias. Vientos en exceso de 30 mph y granizo pequeno son posibles con estas tronadas. Lluvias torrenciales tambien estan ocurriendo con estas tronadas, y pudieran causar inundaciones localizadas. No maneje su vehiculo a traves de las carreteras inundadas. Rayos frecuentes de nube a suelo estan ocurriendo con estas tronadas. Los rayos pueden alcanzar hasta 10 millas de distancia de la tronada. Busque refugio dentro de un edificio o vehiculo. ICP/DSR
Comunicado Especial de las Condiciones del Tiempo Servicio Nacional de Meteorologia San Juan PR 343 PM AST lunes 28 de septiembre de 2020 ...UN AREA DE TRONADAS FUERTES AFECTARA LOS MUNICIPIOS DEL OESTE INTERIOR Y SUROESTE DE PUERTO RICO... A las 3:42 PM AST, tronadas fuertes estaban agrupadas a 7 millas al noreste de Hormigueros. Estas tronadas estaban casi estacionarias. Vientos en exceso de 30 mph y granizo pequeno son posibles con estas tronadas. Lluvias torrenciales tambien estan ocurriendo con estas tronadas, y pudieran causar inundaciones localizadas. No maneje su vehiculo a traves de las carreteras inundadas. Rayos frecuentes de nube a suelo estan ocurriendo con estas tronadas. Los rayos pueden alcanzar hasta 10 millas de distancia de la tronada. Busque refugio dentro de un edificio o vehiculo. ICP/DSR
The San Juan radar (TJUA), 100 km away, was scanning. The volume nearest the first event began at 19:58 UTC.
1 lightning, 1 thunderstorm wind. Local standard time, as filed.
Lightning struck a wooden house in sector Guacio. The house was totally destroyed.
Wind gusts caused downed trees and utility posts in Road PR-348 KM 6.8 in Sector Rosario.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Lightning, San Sebastian | 2020-09-28 | Unknown | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2020Every state in 2020This day in weather historyWarnings in Puerto Rico, September 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 921883, 921884.